This application claims the priority of Australian patent application Serial No. PQ 7802, filed on Aug. 12, 1999.
The present invention relates generally to a ground engaging boundary element. In one form the invention relates particularly to a series of interlocked ground engaging elements together forming garden edging, and will primarily be described with reference to this context. It should be remembered, however, that the invention can have broader use in other wall construction applications to provide a barrier between two areas, for example to conceal goods or machinery from view.
There have been numerous systems proposed in the art for the fabrication of garden edges and retaining structures. In all cases the wall systems proposed do not have ease of installation in either straight or curved runs while allowing for undulations in ground levels and with sufficient strength to retain earthen material. Many thin-walled devices have been proposed but do not have sufficient strength for the majority of applications where reasonable retaining properties are required. Distortion of the garden edging elements can occur.
The garden edging element of the specification of Australian Patent No. 666428 includes as an essential element a stabilising member which makes the device complicated and cumbersome to install in the ground. The specification of U.S. Pat. No. 5,414,956 and German Patent No. 3837815, disclose interlocking garden edging having abutting adjacent edges of adjacent modules. These edging modules do not permit pivoting of adjacent modules so that installation can only occur in straight or fixed configurations.
These prior art specifications do not form part of the common general knowledge in the relevant art.
The present invention provides a ground engaging boundary element comprising:
opposing edge portions at least one of which includes interlocking means being adapted to interlock with an adjacent element to form a section of an elongate boundary structure, said interlocking means being configured to allow articulation of the adjacent elements; and
earth engaging means formed at a lower edge portion of said element and being adapted to embed in the ground, the interlocking means extending to or adjacent the lower edge portion of the boundary element whereby the earth engaging means together with at least part of the interlocking means is embedded in the earth.
Preferably the opposing edge portions in cross section each include a convex shaped surface being adapted to permit articulation of the adjacent interlocked elements so as to provide for non-linear elongate boundary structure.
Preferably the interlocking means comprises either a tongue member or a groove member being shaped complementary to one another and located on opposite edge portions of the element. More preferably the tongue member or the groove member are shaped partly circular in cross section. Most preferably the tongue member is a T-ball tongue member and the groove member is a T-bar slot member.
Preferably the tongue and groove members in the edge portions extend part way therealong such that the members do not extend to an upper edge portion of the element. More preferably when the element is interlocked with an adjacent element in use the tongue and groove members are concealed by the upper edge portion of the element.
Preferably the tongue member is of a reduced length relative to the groove member in use to permit height variation between interlocked elements while still providing concealment of the tongue and groove members.
Preferably the earth engaging means comprises a bevelled lower edge on the element and on the tongue and groove members to facilitate insertion into the earth.